avatar
Cyscom
Cybersecurity Student Community of VIT Chennai
  • CTF EVENTS
  • CATEGORIES
  • TAGS
  • ARCHIVES
  • POSTS
  • ABOUT
Home CyberConverge 2026 The King's Last Recipe
Writeup
Cancel

The King's Last Recipe

The King’s Last Recipe

  • Author: Utkarsh

This is a cryptography-based CTF involving multiple encoding layers and hidden clues.

The original Google Doc contains hidden white-on-white text. Selecting the page contents reveals:

1
K;v>Sk,6xIrfXt3EJw<nlld)t7h9S2RuIR'Diqb/ysC3?NaZ=1h\sT6:su[llzdxGh1!cyWbK'j9XK6sHkkppx57KzH6({(Z@=vkhV4/yak!kv41Hm_LQ'$<ZT)(9E

This string is encoded using Base92 followed by ROT13. Reversing these operations gives a link to a second Google Doc.

The second document contains the encrypted key.

The story in the first document provides the encoding layers in order:

1
64 → 64 → 8 → 32 → 45 → 58 → 62 → 64 → 92

Therefore, the layers must be decoded in reverse order:

1
Base92 → Base64 → Base62 → Base58 → Base45 → Base32 → Octal → Base64 → Base64

Using CyberChef with the corresponding From Base operations reveals:

1
B3LL4_C1A0

Flag

CYS{B3LL4_C1A0}
Edit on GitHub
Trending Tags
authentication idor sql-injection ssti xss

© 2026 Cyscom. Some rights reserved.

Using the Jekyll theme Chirpy.

A new version of content is available.